Alveolar multilayer structure having a metal coating

ABSTRACT

A multilayer structure is disclosed, comprising: at least one first layer comprising a first polymer film that carries, on a first face, a metal deposit, the first face being a free face of the first layer; and at least one second layer comprising a second polymer film. The second layer is joined, in a plurality of junction zones, to the first layer on the first face carrying the metal deposit, the junction zones defining a region of contact between the first layer and the second layer, the first layer and the second layer forming at least one cell outside the contact region.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/018,614, filed Feb. 8, 2016; which is a continuation of U.S. patentapplication Ser. No. 13/700,333, filed Mar. 26, 2013; which is a 371national phase application of International Application No.PCT/FR2011/051223, filed May 27, 2011; which claims priority to FrenchApplication No. 1054073, filed May 27, 2010. The disclosures of each ofthese applications are hereby incorporated by reference in theirentirety.

BACKGROUND OF THE INVENTION

The present invention relates to a multilayer structure comprising: atleast one first layer comprising a first polymer film that carries, on afirst face, a metal deposit, the first face (15) being a free face ofsaid first layer (10); and a second layer comprising a second polymerfilm.

Structures are known that are constituted by a plurality of layers suchas a polymer film, possibly with a metal deposit, a metal film, polymerfoam, fiberglass, rock wool. Stacking such layers seeks to multiply thethermal barriers, so as to thermally insulate the air situated on oneside of the structure from the air situated on the other side.

However, such multilayer structures provide little insulation since airis free to flow between the layers and thus to pass via the sides of thestructure from a space between two layers to another space between twolayers, and this contributes to transferring heat through the multilayerstructure.

It is possible to contain the structure in a frame that holds the edgesof the layers of the structure captive so as to prevent the air fromflowing. However, the material of the frame then acts as a thermalbridge that greatly reduces the thermal insulating properties of thestructure.

SUMMARY OF THE INVENTION

The present invention seeks to remedy those drawbacks.

The invention seeks to propose a multilayer structure having improvedthermal insulation properties.

This object is achieved as a result of the second layer being joined, ina plurality of junction zones, to the first layer on the first facecarrying said metal deposit, the junction zones defining a region ofcontact between the first layer and the second layer, the first layerand the second layer forming at least one cell outside the contactregion.

By means of such provisions, the metallized face of the first filmcarrying the metal deposit is in contact with the volume of air (or ofgas) present in the space between the first film and the second layer.This presents several advantages compared to the prior-art solution inwhich the space is filled by another material such as foam or by fiberssuch as wool. Since such materials are opaque to infrared radiation,infrared radiation is absorbed and then re-emitted by such materials.However, such re-emission is weak since the temperature gradient betweenthe fibers or between the walls of the pores in the foam is very low.The dissipation of heat by radiation by such material is thus verysmall. Even if the first layer is metal, the barrier of the metal toradiant heat transfer is minimized by its contact with the abovematerial, and the metal contributes solely to limiting the transmissionof infrared and far-infrared radiation.

In contrast, in the solution of the invention, since the metal depositis directly in contact with the volume of air (or of gas) which is moretransparent to thermal radiation than foam or fibers, the thermalradiation re-emitted by the metal deposit does not contribute to heatingthe space between the first layer and the second layer.

In addition, given that the metallized face has lower emissivity thanthe other face of the first film (e.g. made of polymer) of the firstlayer, it re-emits less radiation towards the other face (and thusthrough the first layer), and given that the metallized face is opaque,no radiation can pass through the first layer.

This results in better thermal insulation for a structure comprising anassembly of the invention formed of the first layer and of the secondlayer.

Advantageously, the region of contact between the first layer and thesecond layer comprises a set of crossed continuous lines that form agrid, such that the portions of the first layer and of the second layerthat are separated by the lines form a set of closed disjoint cells.

For example, all of the space between the first layer and the secondlayer comprises a set of closed disjoint cells.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be well understood and its advantages appear better onreading the following detailed description of an embodiment shown by wayof non-limiting example. The description refers to the accompanyingdrawings, in which:

FIG. 1 is a perspective and section view of a multilayer structure ofthe invention;

FIG. 2 is a perspective and section view of another configuration of amultilayer structure of the invention;

FIG. 3 is a perspective and section view of another configuration of amultilayer structure of the invention;

FIG. 4 is a perspective and section view of another configuration of amultilayer structure of the invention; and

FIG. 5 is a section view of another configuration of a multilayerstructure of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, the terms “inner” and “outer” respectivelyindicate, with reference to any two adjacent layers, the space betweenthe two layers and the region outside the two layers.

FIG. 1 shows an example of a two-layer structure of the invention. Thefirst layer 10 is constituted by a first polymer film 13 that carries ametal deposit 50 on one of its faces, referred to as its “first” face15.

The polymer film 13 of the first layer 10 may itself be constituted by aplurality of polymer films. For example, the polymer film 13 may beconstituted by a film made of polyethylene (PE) sandwiched between twofilms made of Surlyn® (manufactured by Dupont de Nemours).

A second layer 20, constituted by a second polymer film 23, is fastenedon the first face 15 that carries the metal deposit 50.

Said fastening is performed in known manner, e.g. using a second film 23comprising Nucrel® (manufactured by Dupont de Nemours).

The second film 23 is fastened on the first film 13 in certain selectedjunction zones of the surface of the first film 13. These junction zonestaken together are referred to as the contact region 30.

Outside the contact region 30, the first layer 10 and the second layer20 co-operate to define a space 40 that has a shape that variesdepending on the arrangement of the junction zones forming the contactregion 30. Whatever the configuration, at least a portion of the space40 is in the shape of a cell 42, i.e. in this portion, and at rest, thefirst layer 10 and the second layer 20 form a cell 42 occupying acertain volume, as shown in FIG. 1. A layer is at rest when it is notstressed.

For example, the contact region 30 is configured in such a manner thatthe second layer 20 is quilted when the first layer 10 is plane.

In FIG. 1, the region 30 of contact between the first layer 10 and thesecond layer 20 comprises a set of crossed continuous lines 38 that forma grid, such that some or all of the first layer 10 and of the secondlayer 20 form(s) a set of closed disjoint cells 42 that are separated bythe lines, the cells 42 thus forming a checkerboard.

The continuous lines 38 may be curved or rectilinear.

For example, the first half of the lines 38 are parallel to one another,the other half of the lines 38 being parallel to one another andperpendicular to the lines 38 of the first half, such that the cells 42that are separated by the lines 38 form a rectangular checkerboard, asshown in FIG. 1.

Given that the first face 15 of the first film 10 carrying the metaldeposit 50 is in contact with the volume of air present in the cells 42between the first layer 10 and the second layer 20, or, in equivalentmanner, between the first film 10 and the second film 20, and that themetallized face 15 constitutes the face of the first film 10 having thelowest emissivity, heat flow through the cells 42 is minimized. Thisresults in better thermal insulation for a multilayer structure 1comprising an assembly formed of the first layer 10 and of the secondlayer 20, compared to a multilayer structure in which it is the faceremote from the metallized face 15 of the first film 10 that is incontact with the volume of air present in the cells 42 between the firstlayer 10 and the second layer 20, since said remote face, being made ofpolymer, has higher emissivity.

Furthermore, given that the cells 42 are closed, all of the volume ofair between the first layer 10 and the second layer 20 is held captivein the cells 42, and consequently heat transfers by convection betweenthe two layers are minimized. This results in better thermal insulationthan if the cells 42 were open.

Advantageously, the cells 42 contain a gas that is more thermallyinsulating than ambient air. For example, the gas may be dry air orargon.

In another configuration, each of the above-described cells 42 presentsa hole 425.

The hole may pass through the first layer 10 or through the second layer20.

Advantageously, the cell shape maximizes the springy properties of thesecond layer 20. For example, the cells may be cylindrical in shape,having a base that is circular or hexagonal.

Thus, when it is constituted by deformable layers, the multilayerstructure 1 may be flattened so as to form a thin sheet, since the aircan thus leave the cells 42 via the holes 425. Such a structure is shownin FIG. 2. The total volume of a multilayer structure 1 containing oneor more assemblies formed of such first and second layers 10 and 20 maythus be considerably reduced while it is being transported. For example,the multilayer structure 1, once flattened, may be rolled up so as toform a roll.

Once on site, the multilayer structure 1 may be relieved of stresses andplaced at rest, so as to return to its initial deployed configuration.This initial configuration is achieved by means of the springiness ofthe deformable films that form the structure, which springiness tends tocause the cells 42 to return to their initial convex shape. Oncedeployed, the multilayer structure 1 thus offers good thermalinsulation.

For example, such a structure may be cut to the appropriate size, thenplaced in the spaces between the rafters below the roof of a dwelling soas to improve the thermal insulation of the dwelling.

If the structure 1 is suspended by its top face, the weight of thelayers situated below the top face contributes, under the effect ofgravity, to causing the structure 1 to return to its initial deployedconfiguration. Gravity thus acts in addition to the springiness of thelayers of the structure 1.

The holes 425 may be situated at the tops of the cells 42, passingthrough the second layer 20.

Each cell 42 may present a plurality of holes 425 that are distributedover the first layer 10 and/or over the second layer 20.

In another configuration, the contact region 30 comprises a set ofdisjoint continuous lines 38, such that the portions of the first layer10 and of the second layer 20 that are separated by the lines 38 form aset of disjoint cells 42 that are open to the outside. For example, allof the contact region 30 may be formed of such lines 38, as shown inFIG. 3. The cells 42 are open to the outside via the side edges of thesecond layer 20.

A multilayer structure 1 containing one or more assemblies formed ofsuch first and second layers 10 and 20, may be flattened for beingtransported, then deployed as explained above. In this configuration,the air leaves the cells 42 naturally, since said cells are open to theoutside.

In another configuration, the contact region 30 comprises a set ofdisjoint zones 38, such that the portions of the first layer 10 and ofthe second layer 20 that surround the zones 38 form a set of cells 42that communicate with one another. For example, all of the contactregion 30 may be formed of such zones 38, as shown in FIG. 4.

The cells 42 may also communicate with the outside, e.g. via holes inthe side edges of the second layer 20, or via holes 425 in the cells 42,as explained above.

A multilayer structure 1 containing one or more assemblies formed ofsuch first and second layers 10 and 20, may be flattened for beingtransported, then deployed as explained above. In this configuration,the air leaves the cells 42 naturally, since said cells are open to theoutside.

In all of the above-mentioned embodiments, it is advantageous for thecontact region 30 formed by the set of junction zones joining togetherthe first and second layers 10 and 20 to be of an area that is verysmall compared to the total area of the surface of the first film 10facing the second film 20. The junction zones act as thermal bridgesthrough the multilayer structure since they absorb thermal radiation andare thus emissive. A structure in which thermal bridges are minimized isthus more thermally insulating.

The multilayer structure 1 of the invention may also be built up bysuperposing any number of assemblies, each formed of a first layer 10and/or of a second layer 20, as described above. The second layer 20 isthus in contact with the first layer 10 of the adjacent assembly via aninter-assembly contact region 60, as shown in FIG. 5.

In this configuration, it is advantageous for the contact region 30 ofone assembly and the region 60 of inter-assembly contact with theadjacent assembly not to be superposed, so as to minimize thermalbridges.

When each of the cells 42 presents one or more holes 425 passing throughthe second layers 20, and when the multilayer structure 1 must becapable of being flattened, the first layers 10 are also provided withholes so as to enable the air to escape from the space between thesecond layer 20 of one assembly and the first layer 10 of the adjacentassembly.

Advantageously, the holes are offset between two adjacent assemblies, soas to optimize the thermal insulation provided by the multilayerstructure 1.

Alternatively, the space between the second layer 20 of one assembly andthe first layer 10 of the adjacent assembly may open to the outside viathe side edges of the structure.

In an assembly made up of a first layer 10 and of a second layer 20 asdescribed above, the contact region 30 may be formed of a combination ofcontact lines 38 and/or of contact zones 38, as described above.

Alternatively, the contact region 30 may be formed of contact lines 38or of contact zones 38 of a single type, as described above.

In the invention, some or all of a multilayer structure 1 may be formedof any combination of such assemblies.

For example, the multilayer structure 1 may be constituted by aplurality of superposed assemblies, each made up of a first layer 10 andof a second layer 20 forming disjoint cells 42. In each assembly, someof the cells 42 present holes 425, the cells 42 having holes 425 beingdistributed differently from one assembly to another, such that astraight line perpendicular to the assemblies and passing through thecells always passes through the same number of cells 42 having holes425. Thus, the multilayer structure 1 can be compacted in part only(since the air-filled cells 42 without holes cannot be flattened), butin its compacted state, it has a thickness that is substantiallyconstant.

In the above description, a first layer 10 is a polymer film thatcarries, on one face, a metal deposit, and a second layer 20 is apolymer film.

In the invention, a first layer 10 may also comprise a plurality offilms, and/or the second layer may also comprise a plurality of films.

The multilayer structure 1 of the invention may also include superposingany number of assemblies, with each assembly being formed of a firstlayer 10 and/or of a second layer 20, as described above, and of thirdlayers that are interposed between one or more of said assemblies. Byway of example, a third layer comprises a third polymer film.

Advantageously, the third layer is joined, in a plurality of junctionzones, to the second layer 20 of a first assembly, the junction zonesdefining a contact region having a surface area that is smaller than thesurface area of the second layer 20, and the third layer is also joined,in a plurality of junction zones, to the first layer 10 of anotherassembly, the junction zones defining a contact region having a surfacearea that is smaller than the surface area of the first layer 10. Thethird layer thus makes it easier to assemble together two adjacentassemblies. By way of example, the contact regions are a combination oflines 38 and/or of zones 38, as described above.

The first, second, and/or third layers may optionally be provided withholes 425.

1. (canceled)
 2. A thermally insulating structure comprising: amulti-layer film including a first polymer layer and a metallized layer;and a second polymer layer joined to the multi-layer film by a pluralityof disjoint zones, wherein the plurality of disjoint zones cause thesecond polymer layer to form a set of cells, wherein the multi-layerfilm forms a bottom of each cell of the set of cells and the secondpolymer layer forms a top of each cell of the set of cells, wherein anaperture is present in the top of each cell of the set of cells.
 3. Thethermally insulating structure of claim 2 wherein the second polymerlayer includes a plurality of apertures in the top of each cell of theset of cells.
 4. The thermally insulating structure of claim 2 whereinthe aperture in each cell of the set of cells allows air to flow freelybetween each cell of the set of cells and an ambient environment.
 5. Thethermally insulating structure of claim 2 wherein the first polymerlayer includes a plurality of apertures in each cell of the set ofcells.
 6. The thermally insulating structure of claim 2 wherein eachcell of the set of cells has a rectangular geometry.
 7. The thermallyinsulating structure of claim 2 wherein the second polymer layer isjoined directly to the metallized layer at the plurality of disjointzones.
 8. The thermally insulating structure of claim 2 wherein asurface area of the second polymer layer is greater than a surface areaof the multi-layer film.
 9. The thermally insulating structure of claim2 wherein each cell of the set of cells has four openings positionedbetween adjacent junction zones, wherein the four openings enablecommunication between each cell of the set of cells and four adjacentcells of the set of cells.
 10. The thermally insulating structure ofclaim 9 wherein the thermally insulating structure further comprises: aflattened state wherein the second polymer layer is compressed againstthe multi-layer film; a deployed state wherein the second polymer layeris separated from the multi-layer film by a volume of gas whileremaining joined at the plurality of the disjoint zones; and at leastone side edge that remains open to an ambient environment in both theflattened state and the deployed state.
 11. A multi-layer polymerstructure comprising: a first polymer layer; and a second polymer layerjoined to the first polymer layer by a plurality of disjoint zones,wherein the plurality of disjoint zones cause the second polymer layerto form a set of cells, wherein the first polymer layer forms a bottomof each cell of the set of cells and the second polymer layer forms atop of each cell in the set of cells, wherein an aperture is present inthe top of each cell of the set of cells.
 12. The multi-layer polymerstructure of claim 11 wherein the aperture in each cell of the set ofcells allows air to flow freely into the cell and flow freely out fromthe cell.
 13. The multi-layer polymer structure of claim 11 furthercomprising a metallized layer disposed between the first polymer layerand the second polymer layer.
 14. The multi-layer polymer structure ofclaim 11 wherein the set of cells comprises a grid of rectangular cells.15. The multi-layer polymer structure of claim 11, wherein the firstpolymer layer has a plurality of apertures in each cell of the set ofcells.
 16. The multi-layer polymer structure of claim 11 furthercomprising: a flattened state wherein the second polymer layer iscompressed against the first polymer layer; a deployed state wherein thesecond polymer layer is separated from the first polymer layer by avolume of gas while remaining joined at the plurality of the disjointzones; and at least one side edge that remains open to an ambientenvironment in both the flattened state and the deployed state.
 17. Themulti-layer polymer structure of claim 11 wherein the set of cells havea rectangular geometry and the disjoint zones associated with a firstcell of the set of cells are positioned only at one of more corners ofthe first cell.
 18. The multi-layer polymer structure of claim 11wherein the second polymer layer comprises a copolymer formed fromethylene and methacrylic acid.
 19. The multi-layer polymer structure ofclaim 11 further comprising: a third polymer layer joined to the firstpolymer layer and the second polymer layer by the plurality of disjointzones.